Organic electroluminescent device

ABSTRACT

An organic electroluminescent device includes electrodes, an organic functional layer formed between facing electrodes, and separators for separating one of the electrodes into a strip, wherein the one electrode includes the first film formed with a vapor deposition method and the second film formed into a strip on the first film between the separators, and wherein the separators have dividing sections provided therein for electrically dividing the vapor deposited films formed on the top surfaces of the separators when the first film is formed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic electroluminescent device, amethod of manufacture thereof and an electronic apparatus.

Priority is claimed on Japanese Patent Application No. 2004-125401,filed Apr. 21, 2004, the content of which is incorporated herein byreference.

2. Description of Related Art

In recent years, in electronic apparatuss such as notebook computers,mobile phones and electronic notes, display devices provided with anorganic electroluminescent (hereafter called organic EL) element incorrespondence with a picture element, such as an organic EL device, hasbeen proposed as means for displaying information.

One of such organic EL devices is a passive matrix type (a simple matrixtype) organic EL device. Generally, the passive matrix type organic ELdevice has a plurality of first electrodes formed into a strip extendingin a predetermined direction on a substrate, a plurality of secondelectrodes into the belt shape directed in the direction perpendicularto the first electrodes, and an organic functional layer which issandwiched between the first electrode and the second electrode from thetop and the bottom in a crossing area. The organic functional layerincludes a light-emitting layer which emits light when an electriccurrent passes through the first electrode and the second electrode, andthe passive matrix type organic EL device has a plurality of the organicfunctional layers including the light-emitting layer in correspondencewith one pixel.

The second electrode of a passive matrix type organic EL device isgenerally formed with a vacuum evaporation method. In the vacuumevaporation method, as is shown, for example, in Japanese UnexaminedPatent Application, First Publication No. H11-87063, the secondelectrodes are separated by providing a separator of a predeterminedthickness between areas to have the second electrodes formed thereon,and vapor-depositing the second electrode material from a directionperpendicular or oblique to a substrate.

A display device having a striped electrode structure tends to cause avoltage drop in an extending direction of an electrode, which furthercauses the unevenness of a picture quality. In particular, a displaydevice of increased size has an increased amount of an electric currentpassing through one electrode, so that the above tendency becomesstrong.

The present invention was made with respect to the above-describedproblems, and an object thereof is to provide an organic EL device whichhas a reduced voltage drop in an electrode and is preferably applicableto a substrate to be increased in size.

SUMMARY OF THE INVENTION

For the purpose of achieving the above-described objects, an organicelectroluminescent device according to the present invention haselectrodes, an organic functional layer formed between facingelectrodes, and separators for separating one of the electrodes into astrip, wherein the one electrode includes the first film formed with avapor deposition method and the second film formed into a strip on thefirst film between the separators, and wherein the separators havedividing sections provided therein for electrically dividing the vapordeposited films formed on the top surfaces of the separators when thefirst film is formed.

The vapor deposition method includes a vacuum vapor deposition method, asputtering method and a CVD method (a chemical vapor deposition method).

In the above-described organic EL device, the above-described secondfilm may contact with at least one of two adjacent separators among theabove-described separators.

In the EL device, the belt-shaped second film is formed on the firstfilm which has been formed in between a plurality of separators with avapor deposition method, so that the film thickness of a stripedelectrode is increased. As a result, the organic EL device has a reducedvoltage drop in the electrode and acquires a uniform picture quality,and is preferably applied to a substrate to be upsized.

In addition, in the EL device, the second film for increasing thethickness of the electrode is formed on the first film which has beenformed with a vapor deposition method, so that the coating of the firstfilm avoids the material of the second film from damaging the organicfunctional layer during the formation of the second film. Accordingly,the second film can be formed with various techniques suitable forincreasing the film thickness, such as a droplet ejecting method.

Furthermore, separators have dividing sections provided therein forelectrically dividing a vapor-deposited film formed on the top surfacesof the separators when the first film is formed, so that a short circuitbetween the electrodes through the separator is reliably prevented.

Because the short circuit is prevented by the above-described dividingsection, the second film can contact with at least one of two adjacentseparators among separators, and consequently the second film can bemore thickly formed.

In the above-described organic EL device, a plurality of theabove-described separators include divided separators which are dividedinto at least two parts, and the above-described dividing section isrecommended to be the gap of the above-described divided separators.

In this case, an evaporated film to be formed on the top surface of theseparator is electrically divided by the gap of the divided separator.

The above-described dividing section is desirably a channel provided onthe top surface of the separator.

In this case, a channel provided on the top surface of the separatorelectrically divides an evaporated film to be formed on the top surfaceof the separator.

Next, an electronic apparatus according to the present invention has anorganic EL device as a displaying device. The electronic apparatusaccording to the present invention can be exemplified by, for instance,information processors such as a notebook computer, a mobile phone andan electronic note, a clock and a word processor. By adopting theorganic EL device according to the present invention for the display ofsuch electronic apparatuses, the electronic apparatuses can be providedwith a display having a reduced voltage drop in an electrode and auniform picture quality.

Next, a method for manufacturing an organic electroluminescent devicehaving an organic functional layer formed in between facing electrodesaccording to the present invention, the method includes formingseparators which separate either of the electrodes into a strip, formingan electrode film between the separators with a vapor deposition method,and placing a further electrode material on the electrode film which isformed between the separators which include a divided separator that isdivided into at least two parts, with the vapor deposition method.

In addition, a method for manufacturing an organic electroluminescentdevice having an organic functional layer formed in between facingelectrodes, the method includes forming separators which separate one ofthe electrodes into a strip, forming an electrode film between theseparators with a vapor deposition method, placing a further electrodematerial on the electrode film which is formed in between the separatorswith the vapor deposition method, and providing a channel whichelectrically divides an evaporated film to be formed on the top surfaceof the separator, when the electrode film will be formed.

The organic EL device manufactured by the method has a further electrodematerial placed on the electrode film which is formed in betweenseparators with a vapor deposition method, and thereby has a thickenedfilm on the electrode.

The organic EL device manufactured by the manufacturing method has thethickened film on the electrode, reduces a voltage drop in theelectrode, and acquires uniform picture quality. Accordingly, themanufacturing method is preferably applied to a substrate to beincreased in size.

In addition, the manufacturing method places an electrode material onthe electrode film which is formed with a vapor deposition method, sothat the coverage by the electrode film avoids a liquid contained in theelectrode material from damaging an organic functional layer.

In addition, separators include divided separators which are dividedinto at least two parts, so that the gap of the divided separatorelectrically divides an evaporated film formed on the top surface of theseparator when the first film is formed, and reliably prevents shortcircuiting between the electrodes through the separator.

Alternatively, by providing a channel for electrically dividing theevaporated film to be formed on the top surface of a separator when anelectrode film is formed, a short circuit between the electrodes of theseparator can be reliably prevented.

In the above-described manufacturing method, when the electrode materialis a metal-dispersed ink or an electroconductive paste, a large amountof the material can be placed at a time.

In addition, the above-described electrode material is preferably placedwith a droplet ejecting method.

A droplet ejecting method can place the large amount of the material ata time, and can easily control the amount and position of the materialto be placed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an organic EL device according to the presentinvention.

FIG. 2 is a view of an internal configuration of an organic EL deviceaccording to the present invention.

FIG. 3 is a view on an arrow I-I′ in FIG. 1.

FIGS. 4A and 4B are explanatory drawings for describing a method formanufacturing an organic EL device.

FIGS. 5A and 5B are explanatory drawings for describing a method formanufacturing an organic EL device.

FIGS. 6A and 6B are explanatory drawings for describing a method formanufacturing an organic EL device.

FIGS. 7A and 7B are explanatory drawings for describing a method formanufacturing an organic EL device.

FIGS. 8A and 8B are explanatory drawings for describing a method formanufacturing an organic EL device.

FIGS. 9A and 9B are explanatory drawings for describing a method formanufacturing an organic EL device.

FIGS. 10A and 10B are explanatory drawings for describing a method formanufacturing an organic EL device.

FIGS. 11A and 11B are explanatory drawings for describing a method formanufacturing an organic EL device.

FIG. 12 is an explanatory drawing for describing a method formanufacturing an organic EL device.

FIG. 13 is an explanatory drawing for describing a method formanufacturing an organic EL device.

FIGS. 14A and 14B are explanatory drawings for describing a method formanufacturing an organic EL device.

FIG. 15 is an explanatory drawing for describing the 2nd embodimentaccording to the present invention.

FIG. 16 is an explanatory drawing for describing the 3rd embodimentaccording to the present invention.

FIG. 17 is an explanatory drawing for describing the 4th embodimentaccording to the present invention.

FIG. 18 is a perspective view showing an embodiment of an electronicapparatus according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the next place, referring to the drawings, one embodiment of anorganic EL device, a manufacturing method therefor and an electronicapparatus according to the present invention will be described. In eachdrawing referred to below, there may be cases where each layer and eachmember are drawn with a different scale in order to make them visible inthe drawing.

First Embodiment

FIGS. 1 to 3 are schematic block diagrams which schematically show apassive matrix type organic EL (electroluminescent) display deviceaccording to the present embodiment. FIG. 1 is a plan view, FIG. 2 is aninner block diagram of an organic EL device 1, and FIG. 3 is a view onthe arrow at I-I′ in FIG. 1. As shown in these drawings, the presentorganic EL device 1 mainly includes: a plurality of first electrodes(anodes) 3 with a strip extending to a predetermined direction on asubstrate 2; a plurality of cathode separators (separators) 4 extendingto the direction perpendicular to the extending direction of the firstelectrodes; a bank layer 10 arranged below the cathode separators 4;second electrodes (cathodes) 5 formed between the cathode separators 4;an organic functional layer 6 sandwiched between the first electrode 3and the second electrode 5 from the top and the bottom, in a crossingarea A (a light-emitting area) of the first electrode 3 and the secondelectrode 5; and a sealing section 7 for sealing the first electrodes 3,the cathode separators 4, the second electrodes 5 and the organicfunctional layers 6 with a can.

In FIG. 2, reference character B denotes a cathode-separator-formingarea which is a range where the cathode separator 4 is formed on thesubstrate 2. In the vicinity of one end Ba of thecathode-separator-forming area B, as shown in the drawings, a pluralityof junctions 8 a are formed in a position deviated to the center of thesubstrate from both ends of the cathode separators 4, while beingsandwiched between the cathode separators 4. The junctions 8 a are apart of a connecting terminal 8, and are directly connected to thesecond electrodes 5. In addition, the cathode-separator-forming area Bis the area in which a plurality of the cathode separators 4 are formedon the substrate 2, but more specifically, is the whole area where thecathode separators 4 and areas between the cathode separators 4 exist.

In addition, the first electrode 3 and a connecting terminal 8 extend sothat the end 3 a of the first electrode 3 and the end 8 b of theconnecting terminal 8 can be placed in a position outside a sealingsection 7; to the end 3 a of the first electrode 3, a data-side drivecircuit 100 has a shift register, a level shifter, a video line and ananalog switch is connected; and to the end 8 b of the connectingterminal 8, a scanning-side drive circuit 101 has a shift register and alevel shifter is connected.

As shown in FIG. 3, an organic functional layer 6 is arranged in thestate of being sandwiched between the first electrode 3 and the secondelectrode 5, which are placed so as to face each other, and includes alight-emitting layer 61 which emits a light having a predeterminedwavelength when a current passes between the first electrode 3 and thesecond electrode 5. An organic EL device 1 has a plurality oflight-emitting areas A in which the organic functional layer containingsuch a light-emitting layer 61 is formed, in a matrix form, and therebyhas a function of a display device. In the organic EL device 1 accordingto the present embodiment, a substrate 2 and the first electrode 3 havetranslucency, and are configured so that the light emitted from thelight-emitting layer 61 can be projected from the substrate 2 side. Inaddition, as shown in the drawing, the organic functional layer 6 isaccommodated in the space surrounded by a bank layer 10, the firstelectrode 3 and the second electrode 5. As a result, the organicfunctional layer 6 is prevented from being deteriorated by moisture orair, which enters from outside.

The material of a substrate 2 having translucency includes, forinstance, glass, quartz and a resin (plastic and a plastics film), andparticularly, an inexpensive soda glass substrate is preferably used. Aplurality of the first electrodes 3 are formed of a translucentconductive material metallic consisting of a metal oxide such as indiumtin oxide (ITO) and indium zinc oxide (IZO), are set to have a strip,and are placed at predetermined spacings. The first electrode 3 plays arole in injecting positive holes (hereafter called holes) into anorganic functional layer 6. A connecting terminal 8 is formed of a metalhaving electroconductivity, is set to have a rectangle form, and asshown in the drawing, is arranged so that its own end 8c is placedbetween the cathode separators 4.

On a substrate 2 on which the first electrode 3 and a connectingterminal 8 are formed, an insulation film 9 made of a silicon oxide film(SiO₂) is formed. The insulation film 9 is patterned so that the firstelectrode 3 in a light-emitting area A, the vicinity of the end 3 a ofthe first electrode 3, a junction 8 a and the vicinity of the end 8 b ofthe connecting terminal 8 can be exposed. The insulation film 9 ispatterned so that the junction 8 a can be placed in a position deviatedto the center of the substrate 2 from an end 4 a of a cathode separator4 (one end Ba in a cathode-separator-forming area B).

A bank layer 10 is formed on an insulation film 9 in acathode-separator-forming area B so as not to cover a junction 8 a. Thebank layer 10 is made of an organic material superior in heat resistanceand solvent resistance, such as an acrylic resin and a polyimide resin,and has an opening 10 a formed in a position corresponding to alight-emitting area A. The bank layer also has a thickness set to bethinner than that of a cathode separator 4 and thicker than that of anorganic functional layer 6.

A cathode separator 4 formed on a bank layer 10 is formed of aphotosensitive resin such as polyimide. The cathode separator 4 has adivided structure of being divided into two parts in an orthogonaldirection with respect to the extending direction of the cathodeseparator 4, and a plurality of the separators are formed so that thetwo of them have a predetermined spacing in between them. However, thecathode separators 4 located at the ends of an array direction (the topand bottom ends shown in FIG. 2) need not have the dividing structure.When an evaporated film is formed on the top face of the cathodeseparator 4, the evaporated film is electrically divided by a gap 4 z inbetween the divided two members.

Here, the cathode separator 4 is composed of a different material fromthat of a bank layer 10, so as not to etch the bank layer 10 when thecathode separator 4 is formed, for instance, with a photolithographictechnology. In addition, the cathode separator 4 is formed so that theend 4 b in the width direction at the top of the cathode separator 4 canbe placed outside the edge of the opening 10 a of a bank layer 10.

An organic functional layer 6 is a layered body consisting of a holeinjection/transportation layer 62, a light-emitting layer 61 and anelectron injection/transportation layer 63, and is accommodated in theopening 10 a of the bank layer 10. The hole injection/transportationlayer 62 is formed of a mixture of a polythiophene derivative such aspolyethylene dioxy thiophene, and polystyrene sulfonate. Thehole-injection/transportation layer 62 has the functions of injectingholes into a light-emitting layer 61 and transporting the holes in theinner part of the hole-injection/transportation layer 62.

A light-emitting layer 61 has three types of a red-light-emitting layer61 a for emitting a red light (R), a green-light-emitting layer 61b foremitting a green light (G), and a blue-light-emitting layer 61 c foremitting a blue light (B), and each of the light-emitting layers 61 a to61 c is arranged into a mosaic pattern. The usable material of thelight-emitting layer 61 includes, for example, anthracene, pyrene,8-hydroxyquinoline aluminum, a bisstyrylanthracene derivative, atetraphenyl butadiene derivative, a coumarin derivative, an oxadiazolederivative, a distyrylbenzene derivative, a pyrrolopyridine derivative,a perynone derivative, a cyclopentadiene derivative, athiadiazolopyridine derivative; or the low molecular materials dopedwith rubrene, a quinacridon derivative, a phenoxazone derivative, DCM,DCJ, perynone, a perylene derivative, a coumarin derivative, and/or adiazaindacene derivative.

An electron injection/transportation layer 63 has the functions ofinjecting electrons into a light-emitting layer 61 and transporting theelectrons in the inner part of the electron injection and transportinglayer 63. For the material of the electron injection/transportationlayer 63, for instance, lithium quinolinol, lithium fluoride orbathophen cesium can be preferably used. A metal having a work functionof 4 eV or less, such as Mg, Ca, Ba, Sr, Li, Na, Rb, Cs, Yb and Sm, canbe also used.

A second electrode 5 has a layered structure consisting of a pluralityof films. Specifically, the second electrode 5 has the first film 5 aformed with a vapor deposition method, and the second film 5 b of anauxiliary electrode to be formed on the first film 5 a, in order toincrease the thickness of the second electrode. Here, the first film 5 amay be any of a transmission layer, a reflection layer and a layerincluding the transmission layer and the reflection layer; and thesecond film 5 b is the reflection layer if the first film 5 a is thetransmission layer, or is any layer otherwise. In addition, the secondfilm 5 b is formed with a droplet ejecting method as will be describedbelow.

A material for forming the first film 5 a includes, for instance, Al,Mg, Au, Ag and Ca, and besides ITO, IZO and lithium fluoride LiF. Alayered structure containing the transmission layer and the reflectinglayer in the first film 5 a includes, for instance, a layered film of Caand Al (Ca/Al; transmission layer/reflection layer), Mg/Ag, Ca/Ag, Ba/Agand M/Ag, (where M is at least one of rare earth elements, and ispreferably at least one element among Ce, Yb, Sm, Er, Y, La, Gd(gadolinium), Dy (dysprosium) and Nd (neodymium)). In addition, a filmconsisting of LiF (for instance, LiF/Ca/Al) may be arranged on alight-emitting layer side. When a cathode has a layered structure, thelayer nearer to the light-emitting layer is preferably formed of amaterial having a lower work function.

The first film 5 a is preferably formed with a vacuum vapor depositionmethod in the respect of preventing the light-emitting layer from beingdamaged by heat, but may be formed with another method such as asputtering method and a CVD method. In the present embodiment, the firstfilm 5 a is formed so as to cover the opening 10 a of a bank layer 10.

On the other hand, the second film 5 b is formed on the above-describedfirst film 5 a between a plurality of cathode separators 4, and is alsoformed so as to contact with both of two adjacent cathode separators 4.When the first film 5 a is formed with a vapor deposition method, anevaporated film having the same quality as the first film 5 a is formedon the top surface 4 d of the cathode separator 4, but because thecathode separator 4 has the configuration of a dividing structure, ashort circuit between the second electrodes 5 is reliably prevented bythe gap part 4 z between the cathode separators 4. The material forforming the second film 5 b will be described in detail below.

In addition, on the second film 5 b, a protective layer formed of SiO,SiO₂ or SiN for preventing oxidation may be provided as needed.

A sealing portion 7 is composed of a sealing resin 7 a coated on thesubstrate 2 and a sealing can (a sealing member) 7 b. The sealing resin7 a is an adhesive for bonding the sealing can 7 b to the substrate 2,and is circumferentially coated around the substrate 2 with amicro-dispenser for instance. The sealing resin 7 a is made of athermosetting resin or an ultraviolet-curing resin, and is particularly,preferably an epoxy resin which is one of the thermosetting resins. Inaddition, the sealing resin 7 a employs a material of hardly passingoxygen and moisture therethrough, and prevents flowing water or oxygenfrom invading inside the sealing can 7 b from the clearance between thesubstrate 2 and the sealing can 7 b to inhibit the oxidation of thesecond electrode 5 or a light-emitting layer 61.

The sealing can 7 b has a recess 7 b 1 for accommodating the firstelectrode 3, an organic functional layer 6 and the second electrode 5formed in the inside, and is bonded to a substrate 2 through a sealingresin 7 a. In addition, in the inner side of the sealing can 7 b, agetter material for absorbing or removing oxygen and moisture can beprovided outside a cathode-separator-forming area B, as needed. Thepreferably usable getter material includes, for instance, an alkalimetal such as Li, Na, Rb and Cs, an alkali earth metal such as Be, Mg,Ca, Sr and Ba, an oxide of the alkali earth metal and the hydroxide ofthe alkali metal or the alkali earth metal. The oxide of the alkaliearth metal reacts with water to be changed into a hydroxide, andthereby acts as a dehydrating material. The alkali metal and the alkaliearth metal react with oxygen to be changed to an oxide, and also reactwith water to be changed to a hydroxide, so that they act not only as adeoxidizing material but also as a dehydrating material. Thereby, thegetter material prevents oxidation of an organic functional layer 6 andcan enhance the reliability of a device.

In the next place, a method for manufacturing an organic EL device 1according to the present embodiment will be described referring todrawings. A method for manufacturing an organic EL device 1 according tothe present embodiment includes, for instance, (1) afirst-electrode-forming step (2) an insulation-film-forming step, (3) abank-layer-forming step, (4) a cathode-separator-forming step, (5) aplasma treatment step, (6) a hole injection/transportation layer-formingstep, (7) a light-emitting layer-forming step, (8) an electroninjection/transportation layer-forming step, (9) asecond-electrode-forming step and (10) a sealing step. The manufacturingmethod is not limited to them, but other steps may be removed or addedas needed.

(1) First-electrode-forming Step

A first-electrode-forming step is a step for forming a plurality of thefirst electrodes 3 formed into a strip form (a strip) on a substrate 2,so as to extend in a predetermined direction. Thefirst-electrode-forming step is a step, as shown in FIGS. 4A and 4B, offorming a plurality of the first electrodes 3 made of a metallic oxidesuch as ITO and IZO on a substrate 2, with a sputtering method. Thereby,a plurality of the first electrodes 3 having the strip are formed atpredetermined spacings so that one end 3 a (an upper side in FIG. 4A)can reach the end 2 a of the substrate 2. In the first-electrode-formingstep, a connecting terminal 8 is also formed. The connecting terminal 8is formed as shown in the drawings, so that the one end 8 b can reachthe end 2 b of the substrate 2 and the other end 8 c is placed in theposition deviated to the center of the substrate 2 from the end Ba ofthe bank forming area B.

(2) Insulation-film-forming Step

An insulation-film-forming step is a step for forming an insulation film9 on a substrate 2, the first electrode 3 and the connecting terminal 8,while patterning it as shown in FIGS. 5A and 5B so as to expose thefirst electrode 3 of a light-emitting area A, the vicinity of the end 3b of the first electrode 3, the vicinity of a junction 8 a and the end 8b of a connecting terminal 8. The insulation-film-forming step forms theinsulation film 9 by a plasma CVD method using tetraethoxysilane andoxygen gas or the like as raw materials. The insulation film 9 ispatterned so that the junction 8 a is placed in a position deviated fromthe end Ba of the cathode-separator-forming area B toward the center ofthe substrate 2.

(3) Bank-layer-forming Step

A bank-layer-forming step is a step, as shown in FIGS. 6A and 6B, forforming a bank layer 10 on a cathode-separator-forming area B, so as notto cover a junction 8 a and so as to form an opening 10 a in a positioncorresponding to a light-emitting area A. The bank-layer-forming stepcoats the substrate which has the above-described first electrode 3 andinsulation film 9 already formed thereon, with a photosensitive material(an organic material) having heat resistance and solvent resistance,such as an acrylic resin and a polyimide resin into a thickness notthinner than the organic functional layer 6 and not thicker than thecathode separator 4, and forms an opening 10 a in the positioncorresponding to a light-emitting area A with a photolithographytechnique.

(4) Cathode-separator-forming Step

A cathode-separator-forming step is a step, as shown in FIGS. 7A and 7B,for forming a plurality of cathode separators 4 extending to thedirection perpendicular to the extending direction of the firstelectrode 3, in a strip at predetermined spacings. Thecathode-separator-forming step, at first, applies the photosensitiveresin such as polyimide onto a substrate 2 at a predetermined thicknesswith a spin coating method or the like; etches the photosensitive resinsuch as polyimide coated into the predetermined thickness with aphotolithographic technique, to form a plurality of cathode separators 4which are divided into two in a dividing structure, on acathode-separator-forming area B. The cathode separators 4 are formed sothat the junction 8 a is located in a position between the cathodeseparators, and so that the ends 4 b of the width direction of thecathode separators 4 are placed in a position deviated to the outside ofa light-emitting area A from the end 10 c (an edge) of the bank layer10. In FIGS. 7A and 7B, the whole shape of a cathode separator 4 is aso-called reverse taper shape, but is not limited thereto and may beother shapes.

(5) Plasma Treatment Step

A plasma treatment step is carried out for the purpose of activating thesurface of the first electrode 3, and further surface-treating thesurfaces of a bank layer 10 and a cathode separator 4. Specifically, theplasma treatment step includes the first step of plasma-treating thesurfaces with O₂, to clean the exposed first electrode 3 (ITO), furtheradjust a work function, and make the surfaces of the bank layer 10, theexposed first electrode 3 and the cathode separator 4 makeliquid-repellent; and the second step of plasma-treating the surfaceswith CF₄ to make the surfaces of the bank layer 10 and the cathodeseparator 4 make liquid-repellent. The surface of the cathode separator4 after having been made liquid-repellent preferably has a contact angleof 60 degrees or higher with respect to a material for forming thesecond film 5 b of a second electrode 5, which will be described later.

(6) Hole Injection/transportation Layer-forming Step

A hole injection/transportation layer-forming step is a step for forminga hole injection/transportation layer 62 on an exposed first electrode3, or equivalently, in the opening 10 a of the bank layer, with adroplet ejecting method. The hole injection/transportation layer-formingstep includes ejecting a material for the hole injection/transportationlayer on the first electrode 3 with an inkjet device for instance; andthen drying and heating the ejected ink to form the layer on the firstelectrode 3, as shown in FIGS. 8A and 8B.

The inkjet device ejects a material onto the area to be ejected, byejecting the material of a controlled liquid volume per drop from aejecting nozzle provided in an inkjet head, facing the ejecting nozzletoward a substrate, and further relatively moving the ejecting nozzlewith respect to the substrate 2. In the above step, because the surfaceof the bank layer 10 is made liquid-repellent through theabove-described plasma treatment step, even if the material ejected fromthe ejecting nozzle covers the top surface of the bank layer, thematerial reliably enters the inside of the opening 10 a of the banklayer 10.

(7) Light-emitting Layer-forming Step

A light-emitting layer-forming step is a step, as shown in FIGS. 9A, 9B,10A and 10B, for forming the light-emitting layer 61 containing a lowmolecular material, on a hole injection/transportation layer 62 formedon the first electrode 3. In the light-emitting layer-forming step, ablue-light-emitting layer 61 c is formed as shown in FIGS. 9A and 9B, byat first ejecting a blue-light-emitting layer material in an opening 10a of a bank layer 10 corresponding to a blue-light-emitting area Ac,with a droplet ejecting method using an inkjet device for instance;subsequently a red-light-emitting layer 61 a is formed by ejecting ared-light-emitting layer material in the opening 10 a of the bank layer10 corresponding to a red-light-emitting area Aa; and agreen-light-emitting layer 61 b is formed by ejecting agreen-light-emitting layer material in the opening 10 a of the banklayer 10 corresponding to a green-light-emitting area Ab (see FIGS. 10Aand B).

(8) Electron Injection/transportation Layer-forming Step

An electron injection/transportation layer-forming step is a step, asshown in FIGS. 11A and 11B, for forming an electroninjection/transportation layer 63 on a light-emitting layer 61. In theelectron injection/transportation layer-forming step, the electroninjection/transportation layer 63 is formed by ejecting a material foran electron injection/transportation layer on the light-emitting layer61 with a droplet ejecting method using an inkjet device for instance.The total step of a hole injection/transportation layer-forming step,the light-emitting layer-forming step and the electroninjection/transportation layer-forming step is called an organicfunctional-layer-forming step.

As described above, the organic functional layer 6 of the layered bodyconsisting of a hole injection/transportation layer 62, a light-emittinglayer 61 and an electron injection/transportation layer 63 is formed byejecting the material into the opening 10 a formed on the bank layer 10with a droplet ejecting method. As a result, the buildup of the organicfunctional layer 6 along the side surface of a cathode separator 4 canbe prevented.

(9) Second-electrode-forming Step

A second-electrode-forming step is a step, as shown in FIGS. 12, 13 and14A, 14B, for forming a second electrode 5 between the adjacent cathodeseparators 4, and includes the step for forming the first film 5 a witha vapor deposition method and the step for forming the second film 5 bon the first film 5 a with a droplet ejecting method.

In a step for forming the first film 5 a, a material for forming thefirst film 5 a is deposited on the whole area of thecathode-separator-forming area B from the direction perpendicular to asubstrate 2, through a vapor deposition mask with a single openinghaving the same shape as that of the cathode-separator-forming area B.Here, as described above, the end 4 b in the width direction on the topof the cathode separator 4 is arranged in a position deviated to theoutside of the light-emitting area A from the end of the opening 10 a ofthe bank layer 10. As a result, when the material for forming the firstfilm 5 a is evaporated from the direction perpendicular to the surfaceof the substrate 2, as shown in the drawing, an electrode film can beeasily formed so as to cover the opening 10 a of the bank layer 10.Thereby, the organic functional layer 6 is accommodated in the spacesurrounded by the bank layer 10, the first electrode 3 and the secondelectrode 5 (the first film 5 a) thereby. Accordingly, the organicfunctional layer 6 can be protected from moisture or air invading fromthe outside, then be prevented from the deterioration, and consequentlyacquire the adequate life for emitting light. Similarly, because theopening 10 a of the bank layer 10 is covered by the first film 5 a (anevaporated film), the organic functional layer 6 is avoided from beingdamaged by a liquid content (a dispersing liquid) contained in amaterial for forming the second film 5 b which will be described in thenext place.

In a step for forming the second film 5 b, as will be described below,the material for forming the second film 5 b is placed on the first film5 a with a droplet ejecting method using an inkjet device, and then thecoated film is dried. Then, the second film is baked to obtainelectroconductivity. In addition, if further film-thickening is needed,after the baking has been finished, the material may be printed, driedand baked again.

An inkjet device, as shown in FIG. 13, ejects the electrode material Lof a controlled liquid volume per drop from a ejecting nozzle providedin an inkjet head, faces the ejecting nozzle toward a substrate, andfurther relatively moves the ejecting nozzle with respect to a substrate2, to arrange the electrode material on the substrate 2. In the abovestep, because the surface of a cathode separator 4 is made to belyophobic through the above-described plasma treatment step, even if amaterial ejected from the ejecting nozzle is deposited on the topsurface 4 d of the cathode separator 4 and the like, the materialreliably enters a space between the adjacent cathode separators 4. Awall for trapping the flow of the material to be arranged between theadjacent cathode separators 4, toward left and right directions in FIG.14A, may be previously provided on the substrate 2.

An applicable droplet ejecting method includes various well-knowntechnologies such as a piezo method of ejecting ink by using apiezoelectric element which is an element made of a piezoelectricmaterial, and a bubble method of ejecting a liquid material along withbubbles formed by the heating of the liquid material. Among the methods,the piezo method does not heat the liquid material, so that the methodhas an advantage of not affecting the composition of the material andthe like. In the present embodiment, the above-described piezo method isemployed.

A material used for forming the second electrode 5 is a dispersionliquid of dispersing electroconductive fine particles in a dispersionmedium (a metal-dispersed ink, a Ag-dispersed ink in the presentembodiment). The metallic fine particle containing one of gold, silver,copper, palladium and nickel, and the fine particle of anelectroconductive polymer or a superconductor or the like is used hereas the electroconductive fine particle. The electroconductive fineparticle to be used here can have the surface coated with an organicsubstance in order to improve its dispersibility. A material to becoated on the surface of the electroconductive fine particle includes anorganic solvent such as xylene and toluene, or citric acid. Thedispersion medium for a liquid containing the electrconductive fineparticle is not limited in particular so long as to be capable ofdispersing the above-described electroconductive fine particles and asdoes not cause aggregation, but includes alcohols, a hydrocarbon-basedcompound, an ether-based compound, a polar compound and water. As forthese dispersion medium, a steam pressure at a room temperature,viscosity, the concentration of dispersoid and surface tension arecontrolled. The medium can be used singly or in the mixed state of twoor more mediums. In addition, in order to adjust the surface tension ofthe above-described dispersion medium, it is recommended to add a traceamount of a surface tension modifier containing a fluorine-basedcompound, a silicone-based compound and a nonionic surface active agentin such a range of unreasonably decreasing a contact angle with asubstrate. In addition, the above-described dispersion medium mayinclude organic compounds such as alcohol, ether, ester and ketone, asneeded.

A technique to be used for drying (or baking) the applied film of anelectrode material includes an in-furnace baking method of placing asubstrate in a heating furnace (a baking furnace), and heating anddrying the applied film; a hot-plate method of mounting the substrate ona plate (a hot plate), and heating and drying the applied film throughthe plate; and a vacuum method of placing the substrate in a sealablechamber to reduce pressure in the chamber, and vacuum drying the appliedfilm.

By these techniques, the second film 5 b is formed, as shown in FIGS.14A and 14B, on the first film 5 a, so as to contact with both of twoadjacent cathode separators 4. The second electrode 5 having theabove-described layered structure consisting of the first film 5 a andthe second film 5 b placed thereon acquires a film of which thethickness has been increased. In particular, the second film 5 b ofwhich the material has been placed with a droplet ejecting method canbecome a reliably thick film. When the first film 5 a is formed with avapor deposition method, the electrode film (an evaporated film) isformed also on the top surface 4 d of the cathode separator 4, butbecause a gap 4 z in the cathode separator 4 having the configuration ofa dividing structure electrically divides the evaporated film formed onthe top face 4 d, the short circuit between the second electrodes 5through the cathode separator 4 is prevented.

(10) Sealing Step

Finally, a substrate 2 having the first electrode 3, an organicfunctional layer 6 and the second electrode 5 formed in theabove-described steps, and a sealing can 7 b are sealed through asealing resin 7 a. For instance, the sealing resin 7 a consisting of athermosetting resin or an ultraviolet-curing resin is applied on theperiphery of the substrate 2, and the sealing can 7 b is placed on thesealing resin (see FIG. 3). The sealing step is carried out preferablyin an atmosphere of an inert gas such as nitrogen, argon, and helium. Ifthe sealing step is carried out in atmospheric air, and the secondelectrode 5 has flaws like pinholes therein, water or oxygen invadesinto the second electrode 5 through the flaws and may undesirablyoxidize the second electrode 5.

Then, an organic EL device 1 according to the present embodiment iscompleted by connecting a data side drive circuit 100 installed on asubstrate 2 or outside the substrate 2 to the first electrode 3, and ascanning side drive circuit 101 installed on or outside the substrate 2to the second electrode 5.

In the organic EL device 1, the second electrode 5 has a layeredstructure consisting of the first film 5 a and the second film 5 b toincrease the film thickness of the electrode. In addition, in thepresent embodiment, when the second film 5 b is formed, a large amountof an electrode material is placed with a droplet ejecting method due tothe wall of the cathode separator 4, and consequently the second film 5b is thickened to thicken the film of the second electrode 5. Thethickened film of the second electrode 5 reduces a voltage drop in thesecond electrode 5, and consequently makes picture quality uniform.

An electrode material may be placed by not only a droplet ejectingmethod but also a screen printing method or an offset printing method.

In addition, in the organic EL device 1, a gap 4 z between cathodeseparators 4 electrically divides evaporated films formed on the topsurfaces 4 d of the cathode separators 4, so that a short circuitbetween the second electrode 5 through the cathode separator 4 isreliably prevented. Furthermore, as a result of the prevention of theshort circuit, the second film 5 b can be contacted with at least one oftwo adjacent cathode separators 4, and the second film 5 b can be morethickly formed.

In the above-described embodiment, the low molecular material was usedfor a light-emitting layer 61, but a polymer material may be used. Thepolymer material to be used for the light-emitting layer includes a(poly)para-phenylenevinylene derivative, a polyphenylene derivative, apoly-fluorene derivative, polyvinyl carbazole, a polythiophenederivative, a perylene-based pigment, a cumarin-based pigment, arhodamine-based pigment; or the polymeric material doped with rubrene,perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red,cumarin 6 and quinacridon.

Second Embodiment

In the following, the second embodiment of an organic EL deviceaccording to the present invention will be described with reference toFIG. 15.

In the present embodiment, as shown in FIG. 15, the second electrode 5has the layered structure consisting of the first film 5 a, the secondfilm 5 b and the third film 5 c. A step for manufacturing the organic ELdevice 1 includes, in the step for forming the second electrode 5,repeating (twice in the present embodiment) the steps of placing anelectrode material with a droplet ejecting method, on the electrode film(the first film 5 a) formed by a vapor deposition method, and the stepof drying the placed electrode material. Specifically, the step includesforming the second film 5 b with the droplet ejecting method on thefirst film 5 a formed by the vapor deposition method, and furtherforming the third film 5 c on the second film 5 b with the dropletejecting method. In thus composed organic EL device 1, the secondelectrode 5 has a further increased thickness than that in the firstembodiment, so that a voltage drop in the second electrode 5 is morereliably inhibited.

Third Embodiment

In the following, the third embodiment of an organic EL device accordingto the present invention will be described with reference to FIG. 16.

In the present embodiment as shown in FIG. 16, a channel 4 y is providedon the top surface 4 d of a cathode separator 4. The channel 4 y isprovided so as to extend in the extending direction of the cathodeseparator 4, and electrically divides the evaporated film formed on thetop surface 4 d of the cathode separator 4. When such an organic ELdevice 1 is manufactured, at first, the first film 5 a of the secondelectrode 5 is formed with a vapor deposition method, and then thechannel 4 y is provided on the top surface 4 d of the cathode separator4 with a laser beam irradiation or etching. The channel 4 y may beprovided on the cathode separator 4, before or after the first film 5 aof the second electrode 5 will be or has been formed. In the presentembodiment, the channel 4 y electrically divides the evaporated filmformed on the top surface 4 d of the cathode separator 4, to prevent theshort circuit between the second electrodes 5 through the cathodeseparator 4.

Fourth Embodiment

In the following, the fourth embodiment of an organic EL deviceaccording to the present invention will be described with reference toFIG. 17.

As shown in FIG. 17, an organic EL device 11 according to the presentembodiment has a configuration of connecting a wiring board 20 and anorganic EL substrate (a light-emitting device substrate) 30 with atransfer technique called SUFTLA (Surface Free Technology by LaserAblation) (a registered trademark). The above-described transfertechnique is described, for instance, in Japanese Unexamined PatentApplication, First Publication Nos. H10-125929, H10-125930, H10-125931and the like.

A wiring board 20 includes a multilayer substrate 21, a wiring pattern22 with a predetermined shape formed on the multilayer substrate 21, acircuit (IC) 23 connected to the wiring pattern 22, a TFT (a switchingelement) 24 for driving an organic EL element 31, a TFT junction 25 forconnecting the TFT 24 to the wiring pattern 22, and an organic ELjunction 26 for connecting the organic EL element 31 to the wiringpattern 22.

Here, a TFT junction 25 is formed according to the terminal pattern of aTFT 24, and includes, for instance, a bump (an electroconductiveprotruding portion) 25 a formed by electroless plating and a connectingmaterial 25 b placed on the bump 25 a.

An organic EL substrate 30 includes a transparent substrate 32 ofallowing an emitted light to pass therethrough, the first electrode (ananode) 33 made of a transparent metal such as ITO, an organic functionallayer (a hole injection/transportation layer 34 and a light-emittinglayer 35), the second electrode (a cathode) 36, and a cathode separator37. The electron injection/transportation layer may be formed betweenthe light-emitting layer 35 and the second electrode 36.

In addition, between a wiring board 20 and an organic EL substrate 30, asealing paste 38 is filled and an electroconductive paste 39 forelectrically connecting an organic EL junction 26 with a cathode 36 isarranged.

In the present embodiment, the second electrode 36 includes the firstfilm 36 a formed with an evaporation method and the second film 36 bformed on the first film 36. The second film 36 b is formed with adroplet ejecting method so as to contact with both of adjacent cathodeseparators 37.

As a result, the second electrode 36 acquires a thickened film. Inaddition, in the present embodiment, a channel 37 y is provided on thetop surface of a cathode separator 37, and the channel 37 y electricallydivides the evaporated film formed on the top surface of the cathodeseparator 37. Thereby, the short circuit between the second electrodes36 is avoided.

Fifth Embodiment

FIG. 18 shows one embodiment of an electronic apparatus according to thepresent invention. An electronic apparatus according to the presentembodiment mounts an organic EL device 1 shown in FIGS. 1 to 3 thereonas a displaying device. FIG. 18 is a perspective view showing oneexample of a portable telephone. Reference numeral 1000 denotes a mainbody of a portable telephone, and a reference numeral 1001 denotes adisplay using the above-described organic EL device 1. As describedabove, an electronic apparatus according to the present invention has areduced voltage drop in an electrode, to provide an electronic apparatuswith a display having a uniform picture quality.

In the above, the preferred embodiments according to the presentinvention were described with reference to the attached drawings, but itgoes without saying that the present invention is not limited to theembodiments. It is evident that those skilled in the art can conceivevarious changed or modified examples in a category of a technical ideadescribed in claims, and it is understood that the examples also belongto the technical scope according to the present invention as a matter ofcourse.

1. An organic electroluminescent device comprising: first electrodes;second electrodes having first films formed with a vapor depositionmethod into a strip form and second films formed on the first films intothe strip form; organic functional layers formed between the firstelectrodes and the second electrodes; and separators separating thefirst film into the strip form, having top surfaces on which the firstfilms are formed, and having divided separators that are divided into atleast two parts so as to include gaps, the gaps being dividing sectionselectrically dividing the film parts.
 2. A organic electroluminescentdevice according to claim 1, wherein the second film is formed so as tocontact with at least one of two adjacent cathode separators among aplurality of the separators.
 3. An electronic apparatus having anorganic electroluminescent device according to claim 1 as a displaydevice.
 4. An organic electroluminescent device comprising: firstelectrodes; second electrodes having first films formed with a vapordeposition method into a strip form and second films formed on the firstfilms into the strip form; an organic functional layer formed betweenthe first electrodes and the second electrodes; and separatorsseparating the first film into the strip form, having top surfaces onwhich the first films and channels are formed, the channels beingdividing sections electrically dividing the first films.